WO2003056236A1

WO2003056236A1 - Illumination unit and liquid crystal display device using the unit

Info

Publication number: WO2003056236A1
Application number: PCT/JP2002/013492
Authority: WO
Inventors: Toshio Amaya
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2001-12-25
Filing date: 2002-12-25
Publication date: 2003-07-10
Also published as: EP1460336A4; US20050018416A1; DE60219073D1; JP4146349B2; EP1460336A1; DE60219073T2; JPWO2003056236A1; KR20040071751A; CN1608184A; US7210841B2; KR100688677B1; EP1460336B1; AU2002360006A1

Abstract

A liquid crystal display device, comprising a light source, a light guiding plate for guiding light from the light source in the direction of a liquid crystal panel, a reflective sheet disposed so as to cover the light guiding plate and the light source, a frame member for holding, from the upper side, the light guiding plate and light source (i.e., illumination element) surrounded by the reflective sheet, a rear cover storing the illumination element and fitted to the frame member, and a shield member disposed between the rear cover and the illumination element, wherein the shield member is formed of a material with a large heat conductivity, and shields a clearance between the frame member and the rear cover, a clearance between the rear cover and the illumination element, and a plurality of radiating holes formed in the bottom face of the rear cover, all of which form dust entry routes, to isolate these clearances and holes from a display area.

Description

Light

Lighting unit and liquid crystal display device using the same

〔Technical field〕

The present invention relates to a lighting unit in which a light source is arranged on an end face of a light guide plate and a liquid crystal display device using the same. Rice field

[Technical background]

In recent years, lightweight, thin, and low power consumption of display devices for information devices such as notebook personal computer processors and video devices such as portable televisions, video movies, and car navigation systems. Utilizing this feature, liquid crystal display devices are increasingly used. Many of these liquid crystal display devices adopt a configuration in which a built-in illumination unit illuminates illumination light from behind a display panel in order to realize a bright display screen.

In this lighting unit, an edge-light system in which a light guide plate is placed on the back surface of a display panel and a line light source such as a fluorescent discharge tube is arranged on the end surface of the light guide plate is characterized in that it is thin and has excellent brightness uniformity on a light emitting surface. Therefore, it is often adopted as a backlight system for liquid crystal display devices used in notebook personal computers and the like.

FIG. 6 shows a conventional edge light type illumination unit UT provided with a fluorescent discharge tube, and FIG. 7 shows a liquid crystal display device LD having the illumination unit UT shown in FIG. The lighting unit UT includes a flat transparent light guide plate 1 for transmitting light, a fluorescent discharge tube 2 arranged on two opposing sides of the four sides of the light guide plate 1, and a fluorescent discharge tube 2. By reflecting the light emitted from And a reflection sheet 3 for guiding to the end face D1 of the light guide plate 1. Here, the end face D 1 of the light guide plate 1 is an end face on which the fluorescent discharge tube 2 is provided, and the end face D 2 is an end face on which the fluorescent discharge tube 2 is not provided. The back surface and the end surfaces Dl and D2 of the light guide plate 1 are covered with the reflection sheet 3 including the fluorescent discharge tube 2 to form an illumination element 10. The lighting element 10 is held from above and from the side by the frame member 9, and is held from below by the box-shaped back cover 8 fitted to the frame member 9. It is housed in a housing 30 composed of the member 9 and the back surface force par 8. Then, light correction sheets 4 and 5 are provided on the light exit surface side of the light guide plate 1. The lighting unit UT is formed as described above. Further, a liquid crystal panel 11 and a front cover 12 are mounted on the light emitting surface side of the lighting unit UT. Thereby, the liquid crystal display device LD is formed.

The reflection sheet 3 reflects the light leaking from the light guide plate 1 to the outside of the unit and returns the light into the light guide plate 1 again, and plays a role of increasing the illumination light emitted from the light emission surface. As the reflection sheet 3, a white resin film having high reflectance is used. The reflection sheet 3 may be provided with a printing pattern (not shown) so that the diffusion area of the light increases as the distance from the fluorescent discharge tube 2 as the light source increases. As shown in FIG. 5, the reflection sheet 3 is cut into a predetermined shape so as to cover the back surface and the end surfaces D 1 and D 2 of the light guide plate 1 and the fluorescent discharge tube 2, and is bent along each of the surfaces. Perforations S are provided at specified locations where possible.

Here, a portion around the fluorescent discharge tube 2 (hereinafter, this portion is referred to as a reflector portion 20) and a back surface of the light guide plate 1 are continuously covered with one reflective sheet 3. However, the reflection sheet 3 that covers the reflector portion 20 and the reflection sheet 3 that covers the back surface of the light guide plate 1 are separated, and the reflection sheet 3 may be configured so that both are adhered with double-sided tape. . As shown in FIG. 6, when an integrated reflecting sheet 3 that continuously covers the reflector section 20 and the back surface of the light guide plate 1 is used, the lighting unit UT can be made thinner, and the cost and assembly can be reduced. There is an advantage that the number of standing steps can be reduced.

As the light correction sheets 4 and 5, a diffusion sheet, a prism sheet, or the like is used. By arranging an arbitrary number of sheets of various specifications having various optical characteristics as needed, the light emitted from the light guide plate 1 is diffused and condensed, and the emitted light is equalized and the brightness is increased. Aim.

Both ends of the fluorescent discharge tube 2 are connected by soldering or the like to lead wires (not shown) connected to a power supply unit (not shown) such as an impeller for generating a high-frequency AC. During the operation of the lighting unit UT, a voltage required for lighting the fluorescent discharge tube 2 is applied from the power supply unit through a lead wire. Generally, a high voltage is required to light the fluorescent discharge tube 2. For this reason, in order to protect the electrodes of the fluorescent discharge tube 2 and cover the exposed portion of the lead wire to ensure safety, a rubber holder 7 made of an insulator such as rubber is used to hold the fluorescent discharge tube 2 and the lead. It is attached to the outer circumference of the wire.

On the bottom surface of the box-shaped back cover 8, a plurality of heat radiating holes 15 for emitting heat generated from the fluorescent discharge tube 2 are provided. As described above, the back cover 18 is fitted with the frame member 9 so as to form the housing 30 that houses the lighting element 10.

In the conventional illumination unit UT and the liquid crystal display device LD having the above-described configuration, a gap 16A exists between the back cover 8 and the frame member 9 fitted to each other. In addition, a gap 16 B exists between the back cover 8 and the lighting element 10. These gaps 16A and 16B are naturally formed in structure. Dust that has entered the device during the assembly process of the liquid crystal display device LD and dust that has entered the device from the outside after assembling will cause these gaps 16 A and 16 B, the frame member 9 and the lighting element The liquid crystal panel 11 and the light correction sheets 4 and 5 penetrate into the display area 25 provided with the liquid crystal panel 11 and the light correction sheets 4 and 5 through the gap between the liquid crystal panel 11 and the liquid crystal panel 11. In addition, dust that has entered the inside of the device through the heat radiation holes 15 provided in the back cover 8 also removes the gap 16 B, the frame member 9 and the lighting element. Into the display area 25 through the gap between the first and second elements 10. If dust enters the display area, the output light is blocked, causing uneven brightness. Further, the members in the display area 25 such as the light correction sheets 4 and 5 are damaged by friction with dust. In addition, once dust enters between the liquid crystal panel 11 and the lighting unit UT, it is very difficult to remove the dust without dismantling the display device. Therefore, preventing the intrusion of dust in advance is an important issue in maintenance after the assembly process of the liquid crystal display device LD.

Furthermore, when the heat generated from the fluorescent discharge tube 2 during the operation of the lighting unit UT is radiated from the inside of the unit to the outside through the heat radiation holes 15, the gap between the back cover 8 and the lighting element 10 is reduced. Since the air existing in 16B functions as a heat insulating layer, heat dissipation is insufficient, and various problems due to heat occur.

[Disclosure of the Invention]

The present invention has been made in view of the problems of the related art, and has an object to provide a liquid crystal display device capable of reliably preventing dust from entering a display area and a lighting unit used in the device. The purpose is to provide.

To achieve the above object, an illumination unit according to the present invention comprises: a light source; a light guide plate that is disposed on an end face of the light source, guides light emitted from the light source, and emits light from a light emission surface; A lighting unit including a lighting element including a back surface and an end face of a light plate and a reflecting member covering the light source; and a housing holding the lighting element, wherein the lighting unit is formed between the housing and the lighting element. A shielding member that prevents dust from entering the lighting element through a gap between the lighting element and the end face of the lighting element is disposed between the housing and the lighting element.

According to this configuration, since the gap between the housing and the lighting element is shielded by the shielding member, dust that has entered the unit during the unit assembly process and after the assembly may emit light from the lighting element through the gap. On the exit surface It is possible to prevent intrusion.

The housing has a frame portion that holds the lighting element from the light emitting surface side and the end surface side, and a back surface holding portion that holds the lighting element from the back surface side, and heats the heat inside the unit. A heat radiating hole for emitting the light to the outside may be formed in the back surface holding portion, and the shielding member may be disposed at least between a bottom surface of the lighting element and a bottom portion of the housing.

According to such a configuration, since the shielding member is provided between the back surface holding portion of the housing and the lighting element, dust entering the inside of the housing from the heat radiating hole is exposed to the light emitting surface of the lighting element. The casing, which can prevent the intrusion of the lighting element _c , constitutes the frame part, constitutes a frame member attached to the light emitting surface side of the lighting element, and constitutes the back surface holding part. A back surface holding member that fits with the frame member and accommodates the lighting element; a gap formed between the frame member of the housing and the back surface holding member is shielded by the shielding member; Well ,.

According to this configuration, since the gap formed between the frame member forming the housing and the back surface holding member is shielded by the shielding plate member, dust passes through the gap and the light emitting surface of the lighting element. It is possible to prevent the intrusion into the building.

The shielding member may have a flat plate shape, and an outer periphery of the shielding member may be located between an inner peripheral surface and an outer peripheral surface of the frame member of the housing. Further, the shielding member may have a box shape, and an outer periphery of the shielding member may be located between an inner peripheral surface and an outer peripheral surface of the frame member of the housing.

According to this configuration, the gap formed between the frame member forming the housing and the back surface holding member is shielded by the shielding plate member to be isolated from the lighting element, and formed on the back surface holding member. The heat radiating hole is shielded by the main surface of the shielding member and is isolated from the lighting element.

It is preferable that the shielding member is made of a material having higher thermal conductivity than air. . According to this configuration, since the shielding member made of a material having a higher thermal conductivity than air is provided between the back surface holding portion of the housing and the lighting element, the back surface holding portion is provided. It is possible to radiate heat to the outside of the unit more efficiently from the heat radiating hole than when there is a gap between the lighting element and the lighting element. Therefore, various problems caused by heat can be suppressed, and a highly reliable lighting unit can be realized.

A liquid crystal display device according to the present invention includes an illumination unit having the above-described configuration, and a liquid crystal panel disposed on the light exit surface side of the illumination unit.

According to such a configuration, the above-described effect is obtained in the lighting unit, so that it is possible to prevent dust from entering the display area. Accordingly, luminance unevenness due to intrusion of dust can be eliminated, and the constituent members of the display area can be prevented from being damaged by the dust. In addition, since the device does not need to be disassembled to remove dust that has entered the display area, maintenance is facilitated.

In addition, the lighting unit includes the shielding unit, which is made of a material having a higher thermal conductivity than air as described above, and is disposed between the lighting element and the back surface holding member of the housing. You may.

According to such a configuration, it is possible to efficiently radiate heat as described above in the lighting unit, and thus it is possible to suppress various problems caused by heat. Therefore, a highly reliable device can be realized. The above object, other objects, features, and advantages of the present invention will be apparent from the following detailed description of preferred embodiments with reference to the accompanying drawings. [Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing a configuration of a lighting unit according to Embodiment 1 of the present invention.

Fig. 2 shows the structure of a liquid crystal display device incorporating the lighting unit of Fig. 1. It is sectional drawing which shows typically.

FIG. 3 is a cross-sectional view schematically showing a configuration of a lighting unit according to Embodiment 2 of the present invention.

FIG. 4 is a cross-sectional view schematically showing a configuration of a lighting unit according to Embodiment 3 of the present invention.

FIG. 5 is a schematic development view illustrating the configuration of a reflection sheet used in the lighting unit.

FIG. 6 is a cross-sectional view schematically showing a configuration of a conventional lighting unit. FIG. 7 is a cross-sectional view schematically showing a configuration of a liquid crystal display device incorporating the illumination unit of FIG.

[Best mode for carrying out the invention]

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)

FIG. 1 is a cross-sectional view schematically showing a configuration of a lighting unit according to Embodiment 1 of the present invention. FIG. 2 is a sectional view of a liquid crystal display device incorporating the lighting unit shown in FIG. It is sectional drawing which shows a structure typically.

As shown in FIG. 1 and FIG. 2, the illumination unit according to the present embodiment has a flat plate shape for transmitting light from a fluorescent discharge tube 2 as a light source and a liquid crystal panel 11 to be described later. The light guide plate 1 covers the bottom surface of the light guide plate 1 (that is, the surface opposite to the light emitting surface) and the end surfaces Dl and D2, and the periphery of the fluorescent discharge tube 2 (ie, the reflector portion 20). The reflection sheet 3 arranged in the above and the fluorescent discharge tube 2 and the light guide plate 1 (hereinafter referred to as an illumination element 10) surrounded by the reflection sheet 3 are viewed from above (light emitting surface side). A frame member 9 to be held; a box-shaped back cover 8 fitted with the frame member 9 to hold the lighting element 10 from below; and a box member 9 arranged between the bottom surface of the back cover 8 and the lighting element 10. It mainly comprises a plate-shaped shielding member 13. Further, as shown in FIG. 2, the liquid crystal panel 11 and the front panel are located on the light exit surface side of the illumination unit UT. The liquid crystal display LD is configured by disposing the bars 12. Here, the display area 25 includes the liquid crystal panel 11 and the area below the area where the panel is provided.

When manufacturing the illumination unit UT having such a configuration, the fluorescent discharge tubes 2 are disposed on the two opposing end faces D1 of the light guide plate 1, respectively. A lead wire (not shown) connected to a power supply unit (not shown) such as an inverter for generating a high-frequency alternating current is connected to both ends of the fluorescent discharge tube 2 by soldering or the like. In addition, since a high voltage is applied to the fluorescent discharge tube 2 during operation of the lighting unit, an exposed lead wire (not shown) and an exposed lead wire are provided to protect the electrodes of the fluorescent discharge tube 2 and ensure safety.取り付ける Attach a rubber holder 7 made of an insulator such as rubber to the outer periphery of the fluorescent discharge tube 2. Thereafter, the reflection sheet 3 is provided so as to cover the back surface of the light guide plate 1 and the end surfaces D 1 and D 2 of the light guide plate 1 including the fluorescent discharge tube 2. After the illumination element 10 is formed by covering the light guide plate 1 and the fluorescent discharge tube 2 with the reflection sheet 3 in this manner, the illumination element 10 is disposed above the illumination element 10 (that is, on the light exit surface side) so as to surround the display area. The formed frame member 9 is attached. Thereby, the upper and side portions of the lighting element 10 are held by the frame member 9 from the outer peripheral side. Further, the lighting element 10 to which the frame member 9 is attached is housed in a box-shaped back cover 8 having a plurality of heat radiation holes 15 formed on the bottom surface. Here, a shielding member 13 is provided in advance on the bottom surface of the back surface cover 8, and the frame member 9 and the back surface force bar 8 are arranged so that the lighting element 10 is arranged on the shielding member 13. Is fitted. Thus, the illumination element 10 is held by the back cover 8 from below through the shielding member 13. Further, on the light exit surface of the light guide plate 1 not covered with the frame member 9, that is, on the display area, the light correction sheets 4 and 5 are arranged to complete the lighting unit UT. Then, as shown in Fig. 2, a liquid crystal panel 11 is arranged on the light emitting surface side of the lighting unit UT, and a front cover 12 which is a kind of a housing is mounted thereon, and a liquid crystal display is formed. Complete the device LD. The light guide plate 1 is made of a material such as acrylic having optical characteristics such as transmittance and refractive index that are optimal for light transmission. On the back of the light guide plate 1, a fluorescent discharge tube

A dot pattern or a groove pattern (not shown) in which the diffusion area is changed according to the distance from 2 is provided.

As the reflection sheet 3, a white resin film having a high reflectance is used. Here, a single reflecting sheet 3 continuously covering the back and end faces D 1, D 2 of the light guide plate 1, specifically, as shown in FIG. 3, is cut into a predetermined shape and guided. A reflection sheet 3 in which perforations S are formed corresponding to the end faces D 1 and D 2 of the light plate 1 is used. The reflector section 20 is formed by folding the reflection sheet 3 in a U-shape along the end face D1 from the back side of the light guide plate 1 to surround the fluorescent discharge tube 2. In the reflector section 20, the end of the reflection sheet 3 is fixed to the outer periphery of the light exit surface of the light guide plate 1 with an adhesive 6 such as a double-sided tape. On the other hand, at the end face D2 of the light guide plate 1 where the fluorescent discharge tube 2 is not disposed, the reflection sheet 3 is bent along the end face D2 from the back surface side of the light guide plate 1.

The frame member 9 and the back surface force par 8 are made of a resin material. On the bottom surface of the back cover 8, a plurality of heat radiating holes 15 are formed for releasing the heat emitted from the fluorescent discharge tubes 2 to the outside of the unit when the lighting unit UT operates. By assembling the frame member 9 and the rear surface force par 8 by fitting them together, a housing 30 that houses and holds the illumination element 10 therein is formed.

The shielding member 13 has a flat plate shape, and is larger than the outer periphery of the lighting element 10 and can be stored in the back cover 8 in a plan view of the lighting unit UT. Here, the end of the shielding member 13 is 1 mm or more larger than the inner peripheral surface of the frame member 9 and smaller than the outer peripheral surface of the frame member 9 in a plan view. The shielding member 1 3, thermal conductivity 1 6 9 X 1 0 -. 5 cal · cm "1 · s' 1 · deg- 1 material such as metal having a high thermal conductivity than air is, for example, It has a thermal conductivity of 0.487 cal · cnf ¹ · s- ¹ · deg- ¹ . The light correction sheets 4 and 5 provided on the light exit surface side of the light guide plate 1 are for equalizing and increasing the brightness of the light emitted from the light guide plate 1, and in the present embodiment, In addition, one diffusion sheet 4 and one prism sheet 5 are used. The diffusion sheet 4 is a sheet-shaped optical member used for diffusing light from the fluorescent discharge tube 2 and uniformly irradiating the light to the liquid crystal panel 11. The prism sheet 5 is a transparent resin film having a structure in which triangular regular grooves are cut, and condenses light emitted from the light guide plate 1 to form a liquid.

Β says that it irradiates panel 11. Diffusion sheet 4 and prism sheet

Reference numeral 5 is provided without being bonded to any of the light guide plate 1, the reflection sheet 3, the frame member 9, and the like. The light correction sheet is not limited to the diffusion sheet 4 and the prism sheet 5, but sheets of various specifications having various optical characteristics can be used as appropriate.These light correction sheets may be used as needed. Arbitrary numbers are arranged.

During the operation of the lighting unit UT, the light emitted by turning on the fluorescent discharge tube 2 enters the light guide plate 1 from the end face D1 of the light guide plate 1 in which the fluorescent discharge tube 2 is disposed. Here, in the reflector section 20, since the periphery of the fluorescent discharge tube 2 is covered with the reflection sheet 3, the light emitted from the fluorescent discharge tube 2 is reflected by the reflection sheet 3 and does not leak outside. The light enters the light guide plate 1 efficiently. Also, on the back surface of the light guide plate 1 covered with the reflection sheet 3 and at the end face D2 of the light guide plate 1 where the fluorescent discharge tube 2 is not provided, the light leaked to the outside is reflected by the reflection sheet 3 and again. It is returned into the light guide plate 1. As described above, since the light leakage to the outside can be suppressed by the reflection sheet 3, the amount of light emitted from the light exit surface of the light guide plate 1 can be increased. Further, as described above, since a dot pattern or a groove pattern (not shown) for diffusing light is formed on the back surface of the light guide plate 1, light incident on the light guide plate 1 is formed. Are diffused by the pattern. Therefore, the light emitted from the light exit surface can be made more uniform and higher in brightness.

The light emitted from the light guide plate 1 is transmitted to the diffusion sheet 4 which is After passing through the motion sheet 5, it enters the liquid crystal panel 11. By the diffusion sheet 4 and the prism sheet 5, the light is equalized and the brightness is increased. The liquid crystal panel 11 performs display using the light. In the illumination unit UT and the liquid crystal display device LD of the present embodiment, the shielding member 13 is provided between the reflection sheet 3 that covers the rear surface of the light guide 1 and the rear surface power member 8. For this reason, the gaps 16 A, 16 B and the heat radiation holes 15 serving as a path for dust to enter the display area 25 are shielded by the shielding member 13, and the display area 25 is isolated from the path for entry. It is the configuration that was done. Therefore, dust that has entered the gap 16A from outside after assembling the device, dust that has entered during the assembly process and is present in the gaps 16A and 16B, and through the heat radiation holes 15 Dust that tries to enter from the outside cannot enter the display area 25 because the path to the display area 25 is blocked by the shielding member 13. As described above, according to the configuration of the present embodiment, it is possible to prevent dust from entering the liquid crystal panel 11 of the display area 25, the light correction sheets 4, 5 and the like, so that the luminance It is possible to reduce unevenness and to prevent the members of the display area 25 from being damaged by friction with dust. Also, since there is no need to dismantle the device and remove dust, maintenance of the device after assembly becomes easy.

Further, in such a configuration, since the shielding member 13 is made of a material having a large thermal conductivity, the heat inside the unit is passed through the gap 16B, which is a heat insulating layer filled with air, as in the conventional case. The heat radiation is improved as compared with the case where the heat is radiated to the outside from the heat radiation hole 15. Therefore, various problems caused by heat can be suppressed.

In the present embodiment, one reflection sheet 3 is used to continuously cover the reflector portion 20 and the back surface of the light guide plate 1. As a modification of the present embodiment, for example, a reflector A portion that covers the portion 20 and a portion that covers the back surface of the light guide plate 1 may be separated from each other, and a reflective sheet 3 having a configuration in which the two are bonded with an adhesive or the like may be used. Also, in the present embodiment, the case where two fluorescent discharge tubes 2 are provided has been described, but the number and positions of the fluorescent discharge tubes 2 are not limited to this, such as using one fluorescent discharge tube 2. Absent. Further, a light source other than the fluorescent discharge tube may be used.

(Embodiment 2)

FIG. 3 is a cross-sectional view schematically showing a configuration of a lighting unit UT according to Embodiment 2 of the present invention. In FIG. 3, the same reference numerals as those in FIG. 1 denote the same or corresponding components.

The lighting unit UT of the present embodiment has the same configuration as that of the first embodiment, but differs from the first embodiment in the following points. That is, in the first embodiment, the force S at which the flat shielding member 13 is provided, and in the present embodiment, the box-shaped shielding member 13 ′ is provided, and the shielding member 13 ′ is provided. Lighting element 10 is housed in 1 3 '. A step 9 a is formed at the lower end of the inner peripheral surface of the frame member 9, and the step 9 a and the shielding member 13 ′ are fitted. With such a configuration, the same effects as those of the first embodiment can be obtained. Further, by disposing a liquid crystal display panel and a front cover as shown in FIG. 2 of the first embodiment on the light emitting surface side of the illumination unit UT of the present embodiment, the liquid crystal of the first embodiment is provided. A liquid crystal display device having the same effects as the display device can be realized.

(Embodiment 3)

FIG. 4 is a cross-sectional view schematically showing a configuration of a lighting unit UT according to Embodiment 3 of the present invention. In FIG. 4, the same reference numerals as those in FIG. 1 denote the same or corresponding components.

The illumination cut UT of the present embodiment has the same configuration as that of the first embodiment, but differs from the first embodiment in the following points. That is, in the first embodiment, the back cover 8 and the frame member 9 are separately provided, and by fitting them together, the housing 30 for housing the lighting element 10 is formed. However, in the present embodiment, the frame member 9 and the back surface force par 8 are integrated. A molded housing 30 'is provided. Then, a flat shielding plate 13 is fitted into the bottom surface of the housing 30 ′, and the lighting element 10 is disposed on the shielding plate 13. As described above, in the present embodiment, the lighting element 10 is housed in the housing 30 ′, and the upper, side, and lower portions of the element 10 are held.

In the configuration of the present embodiment, there is no gap 16 A (FIG. 1) between the frame member 9 and the back surface force par 8 as in the case of the first embodiment, and Similarly, the space 16 B between the bottom surface of the housing 30 and the lighting element 10, the heat radiation hole 15, and the shielding member 13 are shielded. Therefore, similarly to the effect of the first embodiment, the effect of preventing dust from entering and the effect of improving heat dissipation can be obtained. In addition, by disposing a liquid crystal display panel and a front cover as shown in FIG. 2 of the first embodiment on the light emitting surface side of the illumination unit UT of the first embodiment, A liquid crystal display device having the same effects as the liquid crystal display device can be realized.

As described above, according to the illumination unit and the liquid crystal display device of the present invention, intrusion of dust into the display area of the liquid crystal display device can be reliably prevented, and uneven brightness due to intrusion of dust is eliminated. In addition, it is possible to prevent components of the display area from being damaged by dust. In addition, since heat dissipation is improved, it is possible to suppress various problems caused by heat generated during operation.

From the above description, many modifications and other embodiments of the present invention are obvious to one skilled in the art. Accordingly, the above description is to be construed as illustrative only, and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. Details of the structure and / or function may be substantially changed without departing from the spirit of the invention. For example, in the above-described first to third embodiments, the case where the present invention is applied to an edge-lit type lighting unit has been described. Is also possible. [Possibility of industrial use]

INDUSTRIAL APPLICABILITY The lighting unit and the liquid crystal display device using the lighting unit according to the present invention are useful as a thin and small liquid crystal display device used for AV / OA / communication device products and the like and a lighting unit thereof. is there.

Claims

Scope of request

1. A light source, a light guide plate in which the light source is disposed on an end face and guides light emitted from the light source and emits light from a light emitting face, and a reflecting member that covers the back and end faces of the light guide plate and the light source. A lighting unit comprising: a lighting element including: a housing for holding the lighting element;

A lighting unit, characterized in that a shielding member for blocking a gap between the housing and an end face of the lighting element is provided between the housing and the lighting element.

2. The housing has a frame portion that holds the lighting element from the light emitting surface side and the end surface side, and a back surface holding portion that holds the lighting element from the back surface side, so that heat inside the unit is removed. A heat radiating hole for discharging to the outside of the unit is formed in the back surface holding portion,

2. The lighting unit according to claim 1, wherein the shielding member is disposed at least between a bottom surface of the lighting element and a bottom portion of the housing.

3. The housing constitutes the frame portion, and a frame member attached to the light emitting surface side of the lighting element, and a frame member which constitutes the back surface holding portion and is fitted with the frame member to form the lighting device. A back surface holding member for housing the element, wherein a gap formed between the frame member of the housing and the back surface holding member and communicating with the light emitting surface of the illumination element is the shielding member. 3. The lighting unit according to claim 2, which is shielded.

4. The lighting unit according to claim 3, wherein the shielding member has a flat plate shape, and an outer periphery of the shielding member is located between an inner peripheral surface and an outer peripheral surface of the frame member of the housing.

5. The shielding member has a box shape, and an outer periphery of the shielding member is located between an inner peripheral surface and an outer peripheral surface of the frame member of the housing. Lighting unit.

6. The lighting unit according to claim 1, wherein the shielding member is made of a material having higher thermal conductivity than air.

7. A liquid crystal display device comprising: the lighting unit according to claim 1; and a liquid crystal panel disposed on a light emitting surface side of the lighting unit.

8. A liquid crystal display device, comprising: the lighting unit according to claim 6; and a liquid crystal panel disposed on a light emitting surface side of the lighting unit.